Results 21 to 30 of about 17,890 (211)

Diastereoselective Formal 1,3-Dipolar Cycloaddition of Trifluoroethyl Amine-Derived Ketimines Enables the Desymmetrization of Cyclopentenediones

open access: yesMolecules, 2023
In this research, a metal-free diastereoselective formal 1,3-dipolar cycloaddition of N-2,2,2-trifluoroethylisatin ketimines and cyclopentene-1,3-diones which can efficiently lead to the desymmetrization of cyclopentene-1,3-diones is developed.
Lin-Qiang Li   +7 more
doaj   +1 more source

Domino Multicomponent Approach for the Synthesis of Functionalized Spiro-Indeno[1,2-b]quinoxaline Heterocyclic Hybrids and Their Antimicrobial Activity, Synergistic Effect and Molecular Docking Simulation

open access: yesMolecules, 2019
An expedient synthesis of hitherto unexplored novel hybrid heterocycles comprising dispiropyrrolidine, N-styrylpiperidone and indeno[1,2-b]quinoxaline units has been developed via domino multicomponent 1,3-dipolar cycloaddition strategy employing a new ...
Abdulrahman I. Almansour   +8 more
doaj   +1 more source

Synthesis of pyrrolizines by intramolecular capture of 1,4-dipolar intermediates in reactions of enamines with dimethyl acetylenedicarboxylate [PDF]

open access: yes, 1981
Solvent polarity and reaction temperature strongly influence the reactions of dimethyl acetylenedicar-boxylate (DMAD) with 1-pyrrolidinyl enamines of acyclic and cyclic ketones. Whereas DMAD and 1-[1-phenyl-2-(phenylthio)ethenyl]pyrrolidine (3) give only
Harkema, S.   +5 more
core   +3 more sources

1,3-Dipolar Cycloadditions of N-Benzyl Furfuryl Nitrones with Electron-rich Alkenes

open access: yesMolecules, 2000
The 1,3-dipolar cycloaddition reaction of N-benzyl-C-(2-furyl)nitrones with electron-rich alkenes gives preferentially trans-substituted 3,5-disubstituted isoxazolidines (endo approach).
Tomas Tejero   +3 more
doaj   +1 more source

Büchwald-Hartwig reaction applied to synthesis of new luminescent liquid crystal triarylamines derived from isoxazoles [PDF]

open access: yes, 2015
© 2015 Taylor & Francis Group, LLC. The present work describes the synthesis and characterization of novel series of triarylamines isoxazoles (TAA) addressed to the organic photovoltaic materials. Diarylisoxazoles were synthesized by sequential [3+2] 1,
Fernandes, T. H. M.   +3 more
core   +2 more sources

Hydrophilic Janus Micelles From an ABC Triblock Copolymer

open access: yesAngewandte Chemie, EarlyView.
An amphiphilic triblock copolymer with poly(ethylene glycol) (PEG) and poly(N‐vinylpyrrolidone) (PVP) coronas self‐assembles into spherical micelles with Janus‐type surface segregation in water. Cryo‐TEM, enabled by selective PVP labeling, and 1H‐NOESY NMR reveal phase separation.
José Muñoz‐López   +5 more
wiley   +2 more sources

Highly Efficient and Diastereoselective Synthesis of New Pyrazolylpyrrolizine and Pyrazolylpyrrolidine Derivates by a Three-Component Domino Process

open access: yesMolecules, 2014
Diastereoselective reactions between 4-formylpyrazoles, N-substituted maleimides and glycine derivates led to new series of pyrazolyldipyrrolo [3,4-a:3',4'-f]pyrrolizines and pyrazolylpyrrolo[3,4-c]pyrroles in good yields.
Jairo Quiroga   +6 more
doaj   +1 more source

Copper(I)-Phosphinite Complexes in Click Cycloadditions: Three-Component Reactions and Preparation of 5-Iodotriazoles [PDF]

open access: yes, 2016
© 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.The remarkable activity displayed by copper(I)–phosphinite complexes of general formula [CuBr(L)] in two challenging cycloadditions is reported: a) the one-pot azidonation/cycloaddition of
Crosbie, P   +3 more
core   +3 more sources

A Convenient, Safe, and Atom‐Economical Route to a Large Portfolio of Grubbs‐Type Catalysts for Olefin Metathesis via Four‐Coordinate Ruthenium Alkylidynes

open access: yesAngewandte Chemie, EarlyView.
It may seem counterintuitive to first target a ruthenium alkylidyne when Grubbs‐type ruthenium carbene complexes are the actual goal. In the end, however, this tactic pays valuable dividends in terms of practicality, atom economy, flexibility as well as safety: the new route provides ready access to a large assortment of catalysts for alkene metathesis
Mingxu Cui, Alois Fürstner
wiley   +2 more sources

Diethyl 4-acetyl-5-(2-nitrophenyl)pyrrolidine-2,2-dicarboxylate

open access: yesActa Crystallographica Section E, 2010
The title compound, C18H22N2O7, was synthesized by the 1,3-dipolar cycloaddition reaction of but-3-en-2-one, diethyl 2-aminomalonate and 2-nitrobenzaldehyde. In the molecule, the pyrrolidine ring possesses an envelope conformation.
Long He
doaj   +1 more source

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